1. Field of Invention
The present invention relates generally to adhesive-free, interlocking tiles and, more specifically, to an improved interlock structure for interlocking an assemblage of contiguous floor tiles with uniformly straight edges.
2. Background Discussion
Adhesive-free, interlocking floor tiles are typically molded of substantially resilient, plastic material and utilize interlock elements formed in the tile edges for effecting connections with adjacent, similar tiles. Typically, the interlock elements are pairs of substantially identical alternating projections and slots of substantially dovetail shapes. The projections and slots are supported by the tile edges to effect mating interlocks with inverted, substantially identical slots and projections, respectively, on other tiles to effect a mating interference fit between contiguous tiles of an assemblage, such as, an assemblage of floor tiles.
The projections serve as the male interlock elements and are typically dovetailed shaped; that is, shaped as truncated triangles with rounded corners in plan view and disposed in alignment along each tile. The male projections are alternately spaced by contiguous slots of substantially the same size and shape as the male projections, but inverted to form the female interlocking elements. Typically therefore, the slots are of identical dovetail shape and those on at least two exposed elements support edges of the tile are joined at right angles. The slots extend completely through these edges to provide female counterparts to the male elements. Interlocking of contiguous floor tiles on-site is effected by vertically aligning the male and female interlock elements of one tile with respective inverted female and male interlock elements of contiguous tiles and then driving the interlocks into resilient interference engagements by means of, for example, a mallet. The integrated installation, when thusly installed over flooring substrates, such as concrete or plywood, requires no adhesives or fasteners, and is therefore often referred to as “adhesive-free.” The male-female element pairs form one set each of the interlock structures disposed along the tile edges so that there is a series of contiguous pairs of projections and slots joined by a common dovetail-shaped sidewall.
For certain floor tile applications it is preferred that the tiles have four edges with one pair thereof joining at right angles to provide one corner of the tile and two uniformly solid, straight edges which define two of the four or more square or rectangular side edges of a multi-sided tile, depending on the particular overall tile shape. The pair of solid edge portions serves as straight, overlying support edges for downwardly facing interlock elements when the tile is installed horizontally. The edges have top surfaces as flush extensions of the top surface of the tile body and provide flat, top surfaces with a pair of solid, straight top edges, thereby simulating a conventional ceramic tile assemblage with linear grout lines or wood flooring with grooves and flush, coplanar top surfaces. An oppositely disposed, and second, pair of edges intersect at right angles to form a second opposite corner of the tile. The second pair of edges are likewise provided with a sequence of male-female interlocks defined by sidewalls which extend completely through the tile edges perpendicular to the plane of the tile to mate with the downwardly-projecting respective female and male interlocks of contiguous, substantially identical tiles. Examples of tiles having such interlock arrangements are disclosed by U.S. Pat. No. 4,287,693 issued on Sep. 8, 1981 to R. E. Collette; U.S. Pat. No. 6,526,705, issued on Mar. 4, 2003 to K. M. MacDonald; and, U.S. patent application Ser. No. 09/884,638, filed Jun. 19, 2001 by T. E. Ricciardelli and assigned to the same assignee as the present invention; all of the references referred to above being incorporated by reference herein and made part hereof.
The extent to which each essentially identical pair of interlock elements can effectively function to prevent tile separations during usage is a function of tile composition and the design of the interlocks with various considerations as to tile resilience and the extent of surface area available for inter-mating surface-to-surface engagement between interlocks, and other relevant factors known to those in the art. Thus, with certain of the prior art interlock structures, the two sides of the tile opposite those with solid edge portions utilize the full tile edge thickness for at least the female cavity sidewalls by molding dovetail slots as through-slots into the tile edges. The resulting tile has a pair of top linear edge portions and a pair of opposite or bottom edge portions with alternating non-linear or undulating edges. Advantageously, the latter may be hidden from view after tile assemblage by the overlying straight and solid top edge portions of contiguous tiles, and therefore, the top surfaces of the final tile assemblages have the desired uniformly straight edge lines and flush, top edge surfaces.
For a given thickness of tile, the pair of flush solid support edges forming the periphery of the top surface account for a portion of the overall tile thickness and consequently reduce the surface areas available for mating engagements between the identical pairs of interlock elements. This is because the female cavities have a reduced depth as a result of being dead-ended on-their underlying solid support edges. The male projections are also limited in height because they cannot extend beyond the planes of the top or bottom surfaces of the tile. As a result, the surface areas available to effect inter-element mating engagements is reduced, which is disadvantageous from a connective integrity standpoint. Conversely, this advantageously results in a reduction in the impact forces required to drive the downwardly-facing interlocks on the top tile edges into mating engagements with upwardly-facing interlocks of adjoining tiles, and consequently reduces the effort required for on-site tile installation.
It would be advantageous to provide a generally planar tile with multiple sides and a top surface having an underlying interlock structure that is adapted to facilitate on-site assemblage and removal of individual tiles with matable interlock structures on contiguous tiles, and yet is resistant to separation of the assemblage during usage.
An object of this invention is to provide an interlocking tile with planar top and bottom surfaces and at least two linear edges extending at right angles to one another having different sets of interlock elements underlying the top edge surfaces which are specifically designed to facilitate on-site installation and removal and replacement, if required, of individual tiles without significantly degrading the resistance to tile edge separations during usage.
Yet another object is to provide an adhesive-free tile assemblage with an interlock structure comprised of multiple pairs of differently constructed interlocks providing acceptable connective interlock integrity while facilitating the ease by which on-site installation assemblage and replacement of individual tiles can be effected with mating tiles having substantially identical, inverted interlock structures thereon.
Yet another object is to provide an edge interlock system for a resilient tile that facilitates the initial connections and aligned orientations between the interlocks of that tile and the interlocks of similarly constructed contiguous tiles.